Measles virus kills dolphins at rate unseen since 1987

Scientists say the strain of measles that is killing dolphins cannot be passed to beachgoers or swimmers. The virus last struck a large number of dolphins 25 years ago, but its cause remains a mystery. NBC’s Anne Thompson reports.

>> reporter: they are some of nature's most beautiful and graceful creatures. the bottle nose
dolphins
are in trouble. from new york to
north carolina
, federal scientists report 357
dolphins
died between
july 1st
of this year, and
august 26th
. a sudden and dramatic increase during a period that typically sees 36 deaths. federal officials say the cause is the morbilly virus. the human cause of the strain causes measles. unlike people, there's no way to vaccinate wild
dolphins
.

>>we're expecting the virus and the impact of the virus is going to spread southward.

>>however, scientists say the strain killing the
dolphins
cannot be passed to beach goers and swimmers. in
dolphins
, the morbillivirus weakens their system, causing them to lose weight and making them susceptible to other diseases. this is the biggest die off of these mammals in 25 years. today the source of the virus remains a mystery. scientists will look to see if contributing factors, such as man made pollution make the
dolphins
more vuler ifable to this fast moving disease.
anne thompson
nbc news, new york.